1. Field of the Invention
This invention relates, generally, to machines that sort envelopes. More particularly, it relates to a high speed flat bed sorter.
2. Description of the Prior Art
Businesses that mail large quantities of envelopes can save postage expenses by pre-sorting the envelopes by ZIP codes, carrier routes, and so on.
One common way to sort envelopes is to momentarily increase the speed of a conveyor belt carrying envelopes after a group of envelopes has been sorted. The momentary increase in speed after each grouping creates a physical separation between grouped envelopes so that a person unloading the envelopes visually observes the physical separation and collects as a unit only those envelopes that are grouped together.
This method works in a satisfactory manner at low conveyor belt speeds, but its performance becomes unacceptable at high speeds. Typically, at higher speeds an ambiguity is created by one or more envelopes that lie between contiguous groups. The operator is then unsure as to which group such intermediate envelope or envelopes belongs. Moreover, the repeated speeding up and slowing down of the belt prevents sorting at extremely high speeds. It also wears out the machinery and requires frequent maintenance and adjustment of parts.
Business-size envelopes are best sorted while held in a vertical plane, as disclosed in U.S. Pat. No. 6,241,460, entitled xe2x80x9cOffset Sorter For Envelopes,xe2x80x9d to the present inventor, which disclosure is hereby incorporated by reference into this disclosure.
However, large envelopes or magazines cannot easily be maintained in a vertical plane because they lack rigidity and collapse under their own weight. Accordingly, the inventive apparatus disclosed in the incorporated disclosure is not the optimal apparatus for sorting such large envelopes or magazines, even though it can be used for such sorting if necessary.
What is needed, then, is an improved apparatus that sorts large envelopes, magazines, and the like, while they are lying flat on a conveyor means. The needed means would eschew the technique of increasing the speed of a conveyor belt between groups of items to physically separate them from one another. Moreover, the needed apparatus would operate at speeds heretofore unattainable yet would have less maintenance requirements than slower devices.
However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified needs could be fulfilled.
The longstanding but heretofore unfulfilled need for an improved flat bed sorter is now met by a new, useful, and nonobvious apparatus for sorting items to be mailed by grouping them into visually ascertainable distinct groups. The items are disposed in a generally horizontal plane because they are large, flexible items to be mailed such as large envelopes, magazines, and the like. The novel structure includes a first conveyor means for transporting the items along a first path of travel. A back wall is disposed in blocking relation to the first path of travel and a rotating frustoconical member is mounted for rotation to said back wall so that items following the first path of travel encounter the rotating frustoconical member and are constrained against further movement along the first path of travel. A second conveyor means transports the items along a second path of travel normal to the first path of travel. The second conveyor means has a first end disposed in cooperative relation to the back wall so that said items encountering the rotating frustoconical member are transported by the second conveyor means along the second path of travel.
A movably mounted barrier means is disposed in alignment with the first conveyor means and in spaced apart relation to the back wall. The barrier means has a first, raised position disposed in vertically spaced apart relation to the first conveyor means so that items following the first path of travel are unimpeded by the barrier means and therefore enter into abutting relation to the frustoconical member mounted for rotation on back wall and are carried along the second path of travel by the second conveyor means.
The barrier means has a second, lowered position disposed in blocking relation to items carried by the first conveyor means so that items following the first path of travel encounter said barrier means before reaching the rotating frustoconical member mounted to the back wall and are impeded from reaching the rotating frustoconical member. The items are then transported along the second path of travel by the second conveyor means. A control means alternately raises and lowers the barrier means in response to predetermined input data relating to postal routes. In this way, said items are sorted into transversely staggered groups so that the groups are clearly and unambiguously distinguishable from one another.
In a preferred embodiment, the barrier means has a conical shape. Although the barrier means could be provided in the form of a single cone-shaped member, the preferred structure includes a pair of cone-shaped members mounted in longitudinally spaced apart relation to one another so that items abutting such cone-shaped members are positioned substantially squarely relative to the first conveyor means. Where a single cone-shaped member is employed, an auxiliary alignment means such as a fixed position guide rail for aligning the trailing end of each item is employed.
The cone-shaped member or members are rotatably mounted to a mounting rod. A pair of transversely disposed, longitudinally spaced apart side walls are secured to opposite ends of the back wall. The mounting rod is disposed in interconnecting relation to the side walls and is supported at its opposite ends by said side walls. The mounting rod is rotatably mounted relative to the side walls so that said mounting rod is rotatable about its longitudinal axis of rotation. The cone-shaped member or members are secured to the mounting rod for conjoint rotation therewith.
A computer-controlled control means raises and lowers the barrier means in response to data containing information about postal routes so that the items are sorted into groups where each group includes items that share a predetermined postal designation. The control means may include a cylinder having a plunger that is connected to a linkage that engages the mounting rod so that actuation of the plunger in a first, retracted direction rotates the mounting rod in a first direction, thereby lifting the barrier means and so that actuation of the plunger in a second, extended direction rotates the mounting rod in a second direction opposite to the first direction, thereby lowering the barrier means.
A primary object of the invention is to provide a constant conveyor speed apparatus for sorting horizontally disposed large envelopes or magazines into distinctly separate groups.
A closely related object is to attain the foregoing object with a device that staggers each group transversely relative to its contiguous groups.
Another closely related object is to provide a device that is capable at operating at speeds in excess of twelve thousand items per hour.
These and other important objects, advantages, and features of the invention will become clear as this description proceeds.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the description set forth hereinafter and the scope of the invention will be indicated in the claims.